7. Abstract Higher olfactory processing is still not well-understood in either insects or vertebrates. Given the current state of knowledge, it appears that the structure of olfactory processing is largely similar in mammals and insects, and so a relatively simple model system such as Drosophila may provide insight into higher olfactory processing in other animals. This project will investigate the lateral horn, an olfactory processing region which is thought to mediate most innate behavioral responses to odors and has been compared to the vertebrate amygdala. The goal of this study is to understand the functional role of synaptic inhibition in lateral horn computations. The experiments proposed here will use in vivo electrophysiological recordings in combination with pharmacology and genetic tools to investigate the connectivity and physiological properties of inhibitory inputs to the lateral horn, as well as their synaptic integration and functional effects on lateral horn output neurons. Understanding how inhibition contributes to olfactory processing in the fly will provide important insights into the neural mechanisms of high-level sensory processing in more complex animals, including humans. This knowledge will ultimately aid in the development of novel treatments for sensory disorders.